This invention relates to cycles such as bicycles, and, more particularly, to a removable attachment that permits oversize tires to be temporarily and removably attached to the rear of the cycle frame, thereby increasing the utility of the cycle in mud, sand, snow, or other difficult terrain.
Bicycling is widely enjoyed as both a recreation and a sport by many people. Historically, bicycling was practiced primarily on dry, hard surfaces such as level or inclined hardtop roads, which give good traction to the rear drive wheel of the bicycle. The advent of the rugged type of bicycle generally termed a "mountain bike" has opened many other areas to bicycling. Steep mountain trails are now routinely traversed on mountain bikes, particularly where the traction is good.
There has also been interest in using mountain bikes on poorer surfaces which do not offer good traction. Some riders have used mountain bikes in mud, sand, and even snow. However, in most instances the standard-size tires used for general-purpose riding do not produce sufficiently good traction and flotation on these poorer surfaces.
One approach to cycling on low-traction surfaces is to build a frame for the cycle that accepts oversize tires that achieve better traction and flotation on such surfaces. Another approach is to build a cycle that uses a caterpillar-tractor propulsion system. In these cases, the frames with oversize tires or caterpillar drives are not suitable for general-purpose street riding, and the rider must therefore have two or more cycles to permit riding on the wide range of terrains. Since mountain bikes may be rather expensive, providing a special frame for difficult terrain, which may be used only occasionally, is outside the reach of most persons. Having two different mountain bikes is also impractical, as the poor-traction terrain is often reached only after passing over conventional surfaces.
There is therefore a need for an improved approach to utilizing popular cycles such as mountain bikes on a variety of surfaces, ranging from conventional dry surfaces to low-traction surfaces such as mud, sand, and snow. The present invention fulfills this need, and further provides related advantages.